Nitric Oxide Derivatives Research Articles

Development of a solid-supported light-triggered nitric oxide donor

Nitric Oxide (NO) photocleavable donors are useful tools for interrogating nitric oxide signalling and have potential use in photopharmacological applications. There is currently intensive research into newer methods to improve NO release and kinetic profiles. Herein, we report the design and synthesis of a solid-supported photocleavable NO donor synthesized by ligating an N-nitroso photocleavable nitric oxide derivative to a TentaGel® polymer resin bead. Illumination with 365 nm light released nitric oxide that could be tracked via a turn-on fluorescence response (λex = 450 nm, λem = 545 nm) and measured using the Griess assay and diaminorhodamine derivatives. These beads were further shown to be compatible with living A549 cells and had the ability to deliver greater concentrations of nitric oxide to cells proximal to a bead versus cells at more distal locations within the same well.

Histidine-Bound Dinitrosyl Iron Complexes: Antioxidant and Antiradical Properties.

Dinitrosyl iron complexes (DNICs) are important physiological derivatives of nitric oxide. These complexes have a wide range of biological activities, with antioxidant and antiradical ones being of particular interest and importance. We studied the interaction between DNICs associated with the dipeptide L-carnosine or serum albumin and prooxidants under conditions mimicking oxidative stress. The ligands of these DNICs were histidine residues of carnosine or His39 and Cys34 in bovine serum albumin. Carnosine-bound DNICs reduced the level of piperazine free radicals in the reaction system containing tert-butyl hydroperoxide (t-BOOH), bivalent iron ions, a nitroxyl anion donor (Angeli's salt), and HEPES buffer. The ability of carnosine DNICs to intercept organic free radicals produced from t-BOOH decay could lead to this effect. In addition, carnosine DNICs reacted with the superoxide anion radical (O2•-) formed in the xanthine/xanthine oxidase enzymatic system. They also reduced the oxoferryl form of the heme group formed in the reaction of myoglobin with t-BOOH. DNICs associated with serum albumin were found to be rapidly destroyed in a model system containing metmyoglobin and t-BOOH. At the same time, these protein DNICs inhibited the t-BOOH-induced oxidative degradation of coenzymes Q9 and Q10 in rat myocardial homogenate. The possible mechanisms of the antioxidant and antiradical action of the DNICs studied and their role in the metabolism of reactive oxygen and nitrogen species are discussed.

Seasonal Oxy-Inflammation and Hydration Status in Non-Elite Freeskiing Racer: A Pilot Study by Non-Invasive Analytic Method.

Freeskiing is performed in an extreme environment, with significant physical effort that can induce reactive oxygen species (ROS) generation and dehydration. This study aimed to investigate the evolution of the oxy-inflammation and hydration status during a freeskiing training season with non-invasive methods. Eight trained freeskiers were investigated during a season training: T0 (beginning), T1-T3 (training sessions), and T4 (after the end). Urine and saliva were collected at T0, before (A) and after (B) T1-T3, and at T4. ROS, total antioxidant capacity (TAC), interleukin-6 (IL-6), nitric oxide (NO) derivatives, neopterin, and electrolyte balance changes were investigated. We found significant increases in ROS generation (T1A-B +71%; T2A-B +65%; T3A-B +49%; p < 0.05-0.01) and IL-6 (T2A-B +112%; T3A-B +133%; p < 0.01). We did not observe significant variation of TAC and NOx after training sessions. Furthermore, ROS and IL-6 showed statistically significant differences between T0 and T4 (ROS +48%, IL-6 +86%; p < 0.05). Freeskiing induced an increase in ROS production, which can be contained by antioxidant defense activation, and in IL-6, as a consequence of physical activity and skeletal muscular contraction. We did not find deep changes in electrolytes balance, likely because all freeskiers were well-trained and very experienced.

Enrichment of Bone Tissue with Antibacterially Effective Amounts of Nitric Oxide Derivatives by Treatment with Dielectric Barrier Discharge Plasmas Optimized for Nitrogen Oxide Chemistry.

Cold atmospheric plasmas (CAPs) generated by dielectric barrier discharge (DBD), particularly those containing higher amounts of nitric oxide (NO) or NO derivates (NOD), are attracting increasing interest in medical fields. In the present study, we, for the first time, evaluated DBD-CAP-induced NOD accumulation and therapeutically relevant NO release in calcified bone tissue. This knowledge is of great importance for the development of new therapies against bacterial-infectious complications during bone healing, such as osteitis or osteomyelitis. We found that by modulating the power dissipation in the discharge, it is possible (1) to significantly increase the uptake of NODs in bone tissue, even into deeper regions, (2) to significantly decrease the pH in CAP-exposed bone tissue, (3) to induce a long-lasting and modulable NO production in the bone samples as well as (4) to significantly protect the treated bone tissue against bacterial contaminations, and to induce a strong bactericidal effect in bacterially infected bone samples. Our results strongly suggest that the current DBD technology opens up effective NO-based therapy options in the treatment of local bacterial infections of the bone tissue through the possibility of a targeted modulation of the NOD content in the generated CAPs.

Changes of oxidative stress indices and antioxidant system in the liver tissue on the administration of some coordination compound of copper, derivatives of thiosemicarbazide

Introduction. Identification, study and testing of new remedies for treatment approaches of diseases, resulting from imbalance between oxidants and antioxidants in favor of oxidants, with potentially destructive potential and pathogenesis in liver disorders is of particular interest due to the increase in incidence and severity of these pathologies. Material and methods. The action of novel local copper coordination compounds, thiosemicarbazide derivatives - CMD-4, CMJ-33 and CMT-67, was evaluated in experiments on white rats after subcutaneous administration in two different doses (0.1 and 1.0 µM/kg) 3 times a week for 30 days. The main indices of oxidative stress were evaluated: the level of malonic dialdehyde (MDA), nitric oxide derivatives (NO), S-nitrosothiols, advanced glycation end products (AGEs), advanced oxidation protein products (AOPP) and ischemia-modified proteins (IMP), and antioxidant system: - superoxidismutase (SOD) and catalase activity (CAT), the level of histidine (His) and total antioxidant activity (TAA) in liver tissue of white rats. Results. The administration of CC resulted in the reduction of oxidative stress indices - MDA, AGEs and S-nitrosothiols, which denotes the antioxidant effect of the studied compounds. The level of NO and AOPP derivatives does not change substantially. When administering CMD-4 (1 µM/kg), SOD activity and catalase function decreased markedly. Changes in the content of His and TAA have been shown to be inconclusive, maintaining within the limits of the values recorded in the control group. Conclusions. The elucidation of the modifications of the free radicals processes in liver tissues, which are the basis of the CC action, broadens the theoretical knowledge about the biological properties of a number of chemical compounds; as well provide new possibilities to explore perspective objects in order to obtain new efficient drug preparations

Enhancement of Nitric Oxide Bioavailability by Modulation of Cutaneous Nitric Oxide Stores.

The generation of nitric oxide (NO) in the skin plays a critical role in wound healing and the response to several stimuli, such as UV exposure, heat, infection, and inflammation. Furthermore, in the human body, NO is involved in vascular homeostasis and the regulation of blood pressure. Physiologically, a family of enzymes termed nitric oxide synthases (NOS) generates NO. In addition, there are many methods of non-enzymatic/NOS-independent NO generation, e.g., the reduction of NO derivates (NODs) such as nitrite, nitrate, and nitrosylated proteins under certain conditions. The skin is the largest and heaviest human organ and contains a comparatively high concentration of these NODs; therefore, it represents a promising target for many therapeutic strategies for NO-dependent pathological conditions. In this review, we give an overview of how the cutaneous NOD stores can be targeted and modulated, leading to a further accumulation of NO-related compounds and/or the local and systemic release of bioactive NO, and eventually, NO-related physiological effects with a potential therapeutical use for diseases such as hypertension, disturbed microcirculation, impaired wound healing, and skin infections.

Photoactivated Release of Nitric Oxide and Antimicrobial Peptide Derivatives for Synergistic Therapy of Bacterial Skin Abscesses.

It is of paramount importance to develop novel approaches for combating bacterial resistance and the integration of different antibacterial mechanisms is essential to achieve synergistic bactericidal efficiency while reducing the associated side effects. Herein, amphiphilic antimicrobial copolymers derived from poly-l-lysine (PLL), black phosphorus quantum dots (BPQDs) as near-infrared (NIR) sensitizer, and S-nitrosocysteamine (SNO) as nitric oxide (NO) donor, are assembled into PELI@BPQD-SNO nanoparticles through electrostatic interactions. Amphiphilic copolymers with isopentanyl grafts on PLL at a ratio of 50% achieve an optimal balance between antibacterial activity and hemolysis rate. Photothermal effect of BPQDs leads to NIR-responsive release of NO and the combination with amphiphilic copolymers mutually enhances long-term inhibition of bacterial growth. In an S. aureus-infected subcutaneous abscess model, the bactericidal rate of PELI@BPQD-SNO/NIR treatment reaches nearly 99.6%, which is significantly higher than those without NO release (38%) or amphiphilic copolymers (24%) or NIR irradiation (17%). PELI@BPQD-SNO/NIR treatment shows full recovery of infected wounds, efficient retardation of inflammatory cells, and reconstruction of blood vessels similar to those of healthy skin. Therefore, the electrostatic assembly demonstrates a promising strategy to deliver charged therapeutic agents and the photoactivated release of NO and amphiphilic copolymers achieves synergistic antibacterial efficacy without using any antibiotics.

Multi-coloured fluorescent sensing toolbox for selective detection of nitroxyl in vitro and ex vivo

Methods for the endogenous detection of nitroxyl (azanone; HNO), the reduced and protonated derivative of nitric oxide (NO), are required to define its cardiovascular function and its key role in chronic pain.

A potential diagnostic serum immunological marker panel to differentiate between primary and secondary knee osteoarthritis.

Inflammation contributes to knee osteoarthritis (KOA) where many immunological mediators participate in its initiation and progression. Most clinicians manage primary (pKOA) and secondary osteoarthritis (sKOA) alike. Whether immunological profiles of pKOA and sKOA differ remains obscure. Hence, we aimed to differentially identify potential serum immunologic diagnostic markers of pKOA and of sKOA. This case control study used 46 KOA patients (pKOA, n = 30; sKOA, n = 16), and 60 age, gender matched controls (normal healthy, n = 30; systemic lupus erythematosus [SLE] disease controls, n = 30) where serum was assayed for cytokines (TNF-α, IL-1β, IL-6, IL-10) and nitric oxide derivatives (NOx). Sandwich ELISA assessed cytokine levels, while the 'Griess assay' quantified NOx levels. The diagnostic accuracy of optimal marker combinations was evaluated by the CombiROC web tool. Compared with pKOA, sKOA serum displayed significantly elevated levels of pro inflammatory cytokines (TNF-α, IL-1β, IL-6) with a concurrent decrease in the anti-inflammatory cytokine, IL-10 (P<0.05). This was reiterated by significantly higher Th1:Th2 (TNF-α: IL-10) serum cytokine ratio observed in sKOA compared to that of pKOA. The CombiROC curves identified TNF-α, IL-1β, IL-6 and NOx as the best performing panel of potential diagnostic markers to discriminate pKOA from control groups (~97% accuracy, 90% Sensitivity [SE] and 98% specificity [SP]), while TNF-α, IL-1β and IL-6 discriminated sKOA from control groups (~100% accuracy, 100% SE, and 98% SP). The study identified discrete serum immune biomarker panels to differentiate between pKOA (TNF-α, IL-1β, IL-6 and NOx) and sKOA (TNF-α, IL-1β and IL-6). These findings may assist in developing distinct therapeutic agents for the two types of KOA.

Genetic susceptibility in air pollution-induced airway inflammation in elderly women

BACKGROUND AND AIM: Evidence is supporting that air pollutants can activate inflammatory responses which increase oxidative stress and further affect respiratory health. So far, epidemiological studies on this pathway have mainly disregarded genetic effects. Thus, we aim to investigate the role of genetic susceptibility in air pollution-induced airway inflammation. METHODS: We used data from 445 women (68–79 years) enrolled in the ongoing cohort study on the influence of air pollution on lung function, inflammation and aging (SALIA) between baseline (years 1984–94) and first follow-up (years 2007–10). Biomarkers of airway inflammation were determined at follow-up in induced-sputum samples (levels of leukotriene (LT)B4, tumour necrosis factor-α (TNF-α), the total number of cells and nitric oxide derivatives). Out of 272 lung function-related single nucleotide polymorphisms, we calculated biomarker-specific weighted genetic risk scores (GRS) using internal weights from elastic net regression. Interactions between GRS and chronic NO2, NOx, PM2.5, PM10, PMcoarse, and PM2.5 absorbance exposure (the centred means of cumulative exposure to each air pollutant over observation time) on inflammation were investigated by adjusted linear regression models. RESULTS:Our results confirm that higher exposure to each air pollutant increase airway inflammation (TNF-α) and additionally, higher exposure to PMcoarse increases LTB4 level. Furthermore, we observed significant gene-environment interaction effects for TNF-α (adj. GRSxNOx: p-value=0.036, adj. GRSxPM2.5: p-value=0.021, adj. GRSxPMcoarse: p-value=0.001) and for LTB4 (adj. GRSxPMcoarse: p-value=0.001). Women with high GRS compared to low GRS had an increased risk of air pollution-induced higher TNF-α level as well as higher LTB4 level. CONCLUSIONS:Genetic susceptibility may play a role in the pathway of chronic air pollution exposure to airway inflammation responses. KEYWORDS: Air pollution, Epigenomics, Female, Long-term exposure, Respiratory outcomes, Risk assessment

Improving Cytotoxicity against Breast Cancer Cells by Using Mixed-Ligand Ruthenium(II) Complexes of 2,2'-Bipyridine, Amino Acid, and Nitric Oxide Derivatives as Potential Anticancer Agents.

Several metal-based molecules that display cytotoxicity against multiple cell lines have been pursued in an attempt to fight against cancer and to overcome the typical side effects of drugs like cisplatin. In this scenario, ruthenium complexes have been extensively studied due to their activity in both in vitro and in vivo biological systems, including various cancer cell strains. We aimed to develop a method to synthesize novel [Ru(NO)(bpy)2L2]2+ complexes containing amino acid ligands by using an alternative Click Chemistry approach, namely the copper azide-alkyne cycloaddition reaction (CuAAC reaction), to construct nitrosyl/nitrite complexes bearing a modified lysine residue. We synthesized a new ligand by Click Chemistry approach and new compounds bearing the unprecedented ligand. Cytotoxicity was assessed by the classical MTT colorimetric assay. MCF-7 and MDAMB- 231 cells were used as breast cancer cell models. MCF-10 was used as a model of healthy cells. Amino acid ligands related to N3-Lys(Fmoc) and the new pyLys were successfully synthesized by the diazotransfer reaction and the CuAAC reaction, respectively. The latter reaction involves coupling between N3-Lys(Fmoc) and 3ethynylpyridine. Both N3-Lys(Fmoc) and the new pyLys were introduced into the ruthenium bipyridine complex I, or cis-[RuII(NO)(NO2)(bpy)2]2+, to generate the common nitro-based complex III, which was further converted to the final complex IV. Results of the MTT assay proved the cytotoxic effect of cis- [RuII(NO)(pyLysO-)(bpy)2](PF6)2 against the mammalian breast cancer cells MCF-7 and MDA-MB231. The viability assays revealed that complex IV, bearing a NO group and a modified lysine residue, was able to release NO and cross tumor cell membranes. In this work, Complex IV was observed to be the most active ruthenium bipyridine complex against the mammalian breast cancer cells MCF-7 and MDA-MB231: it was approximately twice as active as cisplatin, whilst complexes I-III proved to be less cytotoxic than complex IV. Additional tests using healthy MCF 10A cells showed that complexes II-IV were three- to sixfold less toxic than cisplatin, which suggested that complex IV was selective against cancer cells.

Neuropeptides and neurohormones in immune, inflammatory and cellular responses to ultraviolet radiation

Humans are exposed to varying amounts of ultraviolet radiation (UVR) through sunlight. UVR penetrates into human skin leading to release of neuropeptides, neurotransmitters and neuroendocrine hormones. These messengers released from local sensory nerves, keratinocytes, Langerhans cells (LCs), mast cells, melanocytes and endothelial cells (ECs) modulate local and systemic immune responses, mediate inflammation and promote differing cell biologic effects. In this review, we will focus on both animal and human studies that elucidate the roles of calcitonin gene-related peptide (CGRP), substance P (SP), nerve growth factor (NGF), nitric oxide and proopiomelanocortin (POMC) derivatives in mediating immune and inflammatory effects of exposure to UVR as well as other cell biologic effects of UVR exposure.

Acute and chronic effects of intravitreal bevacizumab on lung biomarkers of angiogenesis in the rat exposed to neonatal intermittent hypoxia

Purpose/Aim Intravitreal bevacizumab (Avastin) is an irreversible vascular endothelial growth factor (VEGF) inhibitor used to treat severe retinopathy of prematurity (ROP) in extremely low gestational age neonates (ELGANs). ELGANs who are at the highest risk for developing severe ROP often experience brief intermittent hypoxia (IH) episodes which may cause oxidative damage. We tested the hypothesis that intravitreal Avastin leaks into the systemic circulation during exposure to IH and has adverse effects on biomarkers of pulmonary microvascular maturation, thus leading to pulmonary hemorrhage and long-term pulmonary sequelae. Methods Neonatal rats at postnatal day (PN) 0 (birth) were exposed to either: 1) hyperoxia (50% O2) or 2) neonatal IH (50% O2 with brief episodes of 12% O2) from PN0 to PN14. Room air (RA) littermates served as controls. At PN14, the time of eye opening in rats, a single dose of Avastin (0.125 mg in 5 µL) was injected into the vitreous cavity of the left eyes. A control group received equivalent volume saline. At PN23 and PN45, blood gases, lung-to-body weight ratios, histology, immunofluorescence, and lung biomarkers of angiogenesis were examined. Results At PN23, Avastin increased lung VEGF, nitric oxide derivatives (NOx), and hypoxia-inducible factor (HIF)1a in the hyperoxia-exposed groups, but decreased soluble VEGFR-1 (sVEGFR-1). At PN45, lungs from animals exposed to neonatal IH and treated with Avastin were severely hemorrhagic with morphologic changes in lung architecture consistent with chronic lung disease. This was associated with higher VEGF and NOx levels, and lower insulin-like growth factor (IGF)-I and sVEGFR-1. Conclusions These findings prove our hypothesis that intravitreal Avastin penetrates the blood–ocular barrier in IH and alters lung biomarkers of angiogenesis. Avastin targeting of VEGF could affect normal lung development which may be exaggerated under pathologic conditions such as IH, ultimately leading to vascular permeability, vessel rupture, and pulmonary hemorrhage.

Efficacy and safety of inhaled nebulized sodium nitrite in asthmatic patients

BackgroundNitrite is a physiologic nitric oxide (NO) derivative that can be bioactivated to NO. NO has been shown to attenuate airway inflammation and enhance the anti-inflammatory effect of corticosteroids in the animal model of asthma. Here, we aimed to investigate the efficacy and safety of inhaled sodium nitrite as add-on therapy with inhaled corticosteroid (ICS) in adult patients with persistent asthma. MethodsIn protocol 1, 10 asthmatic patients were administered a single dose of nebulized 15-mg sodium nitrite to assess safety, effect on lung function, and pharmacokinetics of nitrite within 120 min. In protocol 2, 20 patients were randomly assigned to a nitrite (15 mg twice daily) group or a placebo group to assess the efficacy over 12 weeks. The primary outcome was the forced expiratory volume in 1 s (FEV1). The secondary outcomes were other lung function parameters, unplanned asthma-related visits at the emergency department (ED) or outpatient department (OPD), admission days, asthma control test (ACT), and safety. ResultsNebulized sodium nitrite had neither acute adverse effect nor effect on lung function test within 120 min. No blood pressure change was seen. At week 12, FEV1 increased in the nitrite group, whereas there was no change in the placebo group. There were 5 events of asthma exacerbation, 4 ED visits, and one unplanned OPD visit in the placebo group, but none of these was noted in the nitrite group. There was no change in ACT scores in both groups. No adverse event was reported during 12 weeks in the nitrite group. There was no change in methemoglobin levels and sputum inflammatory markers. ConclusionFrom our pilot trial, nebulized sodium nitrite is safe in asthmatic patients, and shows the potential to reduce asthma exacerbation compared with placebo.

Estimation of Nitrite-Nitric Oxide Derivative-In Horses with Intestinal Colic by ESR Spectroscopy.

Diseases of the gastrointestinal tract of horses are caused by many factors and have a complex pathogenesis. Developing effective methods of differential diagnostics is of high fundamental and applied importance. The pathogenesis of diseases of the digestive tract of horses accompanied by the development of inflammation and oxidative stress, can be associated with a lack of the nitrogen monoxide which controls many signaling pathways in the body. The level of the nitric oxide (NO) is involved in the regulation of the immune and nervous systems, the tone of all the blood vessels, and the courses of many pathological processes. The nitric oxide activates guanylate cyclase (sGC) and leads to vascular relaxation. The aim of this investigation was to study the metabolites of nitric oxide in horses suffered from intestinal diseases. The levels of nitric oxide in the blood serum of horses depending on their age and health state was studied. The concentration of nitrites in the blood serum of horses aged 6–25 years was 3.4 ± 4.2 μM, and in the young horses (1–5 years) the level of this indicator was 8.2 ± 5.4 μM. A sharp decrease in nitrite was observed in all the horses with intestinal diseases of 2 ± 0.9 μM, especially with tympanitic caecun of 0.6 ± 0.4 μM and with spasmodic colic of 1.8 ± 0.5 μM. The level of nitrosylhemoglobin HbNO in the blood of the diseased animals was higher than that in clinically healthy horses, regardless of age.

Co-administration of prazosin and propranolol with glibenclamide improves anti-oxidant defense system in endothelial tissue of streptozotocin-induced diabetic Wistar rats.

Background Due to increasing prevalence of diabetes and associated endothelial dysfunction, this study was carried out to investigate the effects of co-administration of adrenoceptor blockers (prazosin and propranolol) and glibenclamide on plasma biomarkers of endothelial functions in diabetic rats. Methods Experiments were carried out on 35 male Wistar rats (170-200g). They were divided into seven groups (n=5) as follows: normal control, diabetic control, diabetic+glibenclamide (GLB-5mg/kg/day), diabetic+ prazosin (PRZ-0.5mg/kg/day), diabetic+PRZ+GLB, diabetic+propranolol (PRP-10mg/kg/day), diabetes+PRP+GLB. Experimental diabetes was induced with streptozotocin (60mg/kg) and drugs were administered orally for 3 weeks. Blood pressure was measured and animals were sacrificed afterwards. Blood samples were collected by cardiac puncture, and major marker of endothelial functions, nitric oxide derivatives (NOx), as well as superoxide dismutase (SOD) and malondialdehyde (MDA) were measured on the plasma. The aorta was harvested for histological examination. Data were subjected to descriptive statistics and analysed using ANOVA at α 0.05. Results There was a significant increase in levels of NOx and SOD, and a decrease in MDA level in diabetic treated groups compared to diabetic control. Mean blood pressure increased in diabetic control and diabetic+GLB group when compared with normal control, while it was mildly reduced in diabetic group treated with PRZ and PRP, and co-administered GLB. More so, Aorta histology was altered in diabetic control groups when compared with normal control and all diabetic treated groups. Conclusions Results from this study suggest that PRZ, PRP, and GLB (singly and in combined therapy) could have a restorative effect on endothelial functions in diabetes.

Identification of caffeic acid and rutin by UHPLC MS/MS and antioxidant activity of Commelina erecta Lineu. in cell culture.

The Commelina erecta L. (C. erecta) also known as erva-de-santa-luzia is reported by local population to have medical properties against some pathological conditions. In this study, two extracts of C. erecta leaves (aqueous and ethanolic) were phytochemically analysed and evaluated for their in-vitro antioxidant activities by DPPH, TBARS, NO assays and cell viability assays. The ultra-high performance liquid chromatography followed by tandem mass spectrometry analysis showed the presence of rutin and caffeic acid in aqueous and ethanolic extract. The total polyphenols in aqueous and ethanolic extracts found were 142.7 ± 3.0 and 123.1 ± 5.8 μg/mL of GAE, respectively. The ethanolic extract (5 mg/mL) inhibits TBARS by 33.8%, and the aqueous extract (5 mg/mL) exhibited scavenger property against nitric oxide derivatives to an extent of 77.8%. In cell culture, both extracts improved cell survivability under H2O2 induced oxidative stress. Thus, C. erecta extract is a good candidate to become a phytotherapic medicine.

Near-infrared fluorescent probe for imaging nitroxyl in living cells and zebrafish model

Nitroxyl (HNO) is one of the important derivatives of nitric oxide (NO). It was intertwined with various biological and pharmacological events as a well-defined active molecule. Developing fluorescent probes for high specific and in situ trapping of HNO in living samples is still challenging. In this project, we constructed a near-infrared (NIR) metal-free fluorescent probe (DCM-P) for monitoring HNO in vitro and in vivo. The novel probe, DCM-P, contains a dicyanomethylene-4H-pyran (DCM) fluorophore as the reporter and a triarylphosphine as the recognition moiety. Upon exposure to HNO, the probe emits fluorescence at the wavelength of 688 nm, which belongs to near-infrared region and endows great beneficial for imaging in vivo. Moreover, DCM-P shows high chemoselective detection and fast response to HNO in the presence of various biological relevant reductants, and is successfully employed to trap nitroxyl in different living cells and zebrafish models. These results suggest that DCM-P is a suitable near-infrared metal-free fluorescent probe for motoring nitroxyl in living samples.

Cold atmospheric plasma (CAP) differently affects migration and differentiation of keratinocytes via hydrogen peroxide and nitric oxide-related products

BackgroundA promising approach to treat infected chronic wounds is the treatment with “cold” atmospheric plasma (CAP) that has a broad antibacterial spectrum and can enhance microcirculation. Dielectric barrier discharge (DBD) devices generate CAP containing reactive species, leading to acidification and the accumulation of hydrogen peroxide (H2O2), nitrite and nitrate within the treated tissue/liquids. ObjectiveSince CAP produced species may affect wound healing and cell behavior, we investigated the possible DBD/CAP-induced effects on human keratinocytes. MethodsPrimary keratinocytes were treated by a DBD device (13.5 kV, 300 Hz; 0–300 s). DBD-induced changes (pH; nitrite, nitrate; H2O2) in treated media were evaluated. As control and to investigate the impact of the CAP-produced species, equivalents amounts of H2O2, HCL, nitrite and nitrate as obtained by CAP treatments (0, 60, 300 s) were added separately or combined to keratinocytes. Cell viability and proliferation were determined by live cell imaging and a resazurin-based assay. Gap closure rates were assessed by migration assays. Differentiation/proliferation states were determined by qRT-PCR analysis of KI67 and involucrin. ResultsWe found that even longer CAP-treatment times (300 s) did not reduce cell viability. However, migration/proliferation was affected by longer treatments resulting in a delay of gap closure in migration assays. The mRNA expression of involucrin and KI67 showed a pro-differentiation effect induced by longer CAP treatment. Similar effects could be induced by adding H2O2 in amounts found after a 300 s CAP treatment. The effects were reversed by catalase. Shorter CAP treatment (60 s) did not reveal pro-differentiation effects, but significantly accelerated gap closure. Lower H2O2 concentrations, equivalent to a 60 s CAP treatment, induced also upregulation of involucrin, which in turn could be diminished by low concentrations of nitrite/nitrate, indicating a potential mediation of H2O2-induced effects by parallel CAP-induced accumulation of these nitric oxide derivatives. ConclusionCAP treatment theoretically could kill several birds with one stone—overcome bacterial contamination, improve microcirculation and additionally compensate missing H2O2 and nitric oxide— facilitating wound healing. However, clinical CAP treatment must be well balanced to avoid possible unwanted side effects, such as a delayed healing process and tissue damage.

Homeostasis in Topical Photoprotection: Getting the Spectral Balance Right.

The solar radiation range has harmful and beneficial effects. Sunscreens, which selectively block specific spectral regions, may potentially interfere with skin homeostasis. For instance, the ultraviolet (UV) B waveband produces erythema and DNA damage; simultaneously, it induces pre-vitamin D3 synthesis. UVA1 and visible light can both induce pigmentation in skin phototypes IV–VI, and act in synergy to induce erythema and persistent pigment darkening. In contrast, UVA may contribute to blood pressure control and cardioprotection by inducing release of nitric oxide from intracutaneous photolabile nitric oxide derivatives. Finally, infrared A radiation alters the collagen equilibrium of the dermal extracellular matrix but is involved in the regulation of body temperature and in nitric oxide release, with a potential beneficial impact on blood pressure regulation. Ideally, photoprotection should thus be performed with a neutral density filter, mitigating all radiation ranges homogeneously, to maintain solar spectrum homeostasis. Natural compounds such as mycosporine-like amino acids are promising natural UV radiation-filtering compounds for an improved homeostasis with our environment. Lastly, we should not forget individual characteristics and behavior, as homeostasis differs according to individual phototypes and skin exposure behaviors.